The Chicago Bears boosted their roster Saturday by adding running back Marion Barber and nose tackle Amobi Okoye. But they also might be on the verge of losing Olin Kreutz, their six-time Pro Bowl center.

Kreutz, who has spent 13 seasons with the Bears, appears to be on his way out of Chicago with contract negotiations going nowhere.

Barber was released this week after spending six seasons with the Cowboys and running for 4,358 yards and 47 touchdowns -- sixth in the NFL during that span. He added 1,280 receiving yards.

Bears starting running back Matt Forte, who's making a $550,000 base salary and wants a long-term contract, told the Tribune that the Barber deal isn't a big deal to him.

"I kind of got my mind put to ease by (general manager Jerry Angelo)," Forte said. "He had been in talks with my agent since the end of the lockout and even before that, and he kind of said that a deal would get done. He assured us repeatedly that a deal would get done. Where I'm from and how I was raised, when somebody gives you their word, that goes a long way."

The Bears also addressed their defense, agreeing to a one-year deal with Okoye just hours after the Houston Texans released him.

The youngest first-round draft pick in NFL history when he was taken 10th overall in 2007 at age 19, Okoye had a career-high 44 tackles in 2010, including three sacks. But the Texans spent six of their eight draft picks on defensive players, and new coordinator Wade Phillips plans to use Shaun Cody and Earl Mitchell at nose tackle, leaving Okoye out of the mix.

In four seasons with Houston, Okoye had 138 tackles, 11 sacks, two forced fumbles and two fumble recoveries.

The Bears also re-signed Corey Graham, a cornerback and special-teams contributor, to a one-year deal and waived guard Herman Johnson.

Graham has appeared in 61 games over four seasons with the Bears and recorded 111 tackles, one interception and nine pass breakups. His 82 special-teams stops rank second to Adrian Peterson's 110 on Chicago's list since the statistic was first recorded in 1995.